staging: ccree: document spinlock usage

Document spinlock usage to protect against concurrent
access to HW register which must occur a single
request at a time.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/ccree/ssi_request_mgr.c b/drivers/staging/ccree/ssi_request_mgr.c
index 65c4d9f3f262f4968951a7152e51745b3f42f8cf..1d9c0381059b74fc129a735e974a6a94b23487c7 100644 (file)
--- a/drivers/staging/ccree/ssi_request_mgr.c
+++ b/drivers/staging/ccree/ssi_request_mgr.c
@@ -43,6 +43,9 @@ struct ssi_request_mgr_handle {
        u32 req_queue_tail;
        u32 axi_completed;
        u32 q_free_slots;
+       /* This lock protects access to HW register
+        * that must be single request at a time
+        */
        spinlock_t hw_lock;
        struct cc_hw_desc compl_desc;
        u8 *dummy_comp_buff;